Block gbease testing apparatus



Sept. 25, 1945. H. G. SMITH BLOCK GREASE TESTING APPARATUS Filed March12, 1945 3 Sheets-Sheet 1 HEL G. SMITH Sept. 25, 1945.

H. G. SMITH BLOCK GREASE TESTING APPARATUS Filed March 12, 1945 3She'ets-Sheet 2 HERSCHL ca. SMITH P 1945. H. G. SMITH 2,385,656

BLOCK GREASE.- TESTING APPARATUS Filed March 12,. 1945 s Sheets-Sheet sPatented Sept. 25, 1945 UNITED STATES PATENT OFFICE BLOCK GREASE TESTINGAPPARATUS Herschel G. Smith, Wallingford, Pa., assignor to Gulf OilCorporation, Pittsburgh, Pa., a corporation of Pennsylvania I IApplication March 12, 1945, Serial No. 582,401

6 Claims.

This invention relates to block grease testing apparatus useful fordetermining and comparing the rate of consumption or wearingcharacteristics of blocks of different hard greases when subjected tothe rubbing action of a smooth hard surface under controlled conditionsof tempera ture, feeding pressure and surface speed etc, whereby areliable indication of the wearing characteristics of the grease thatmay be expected from its use in actual service may .be obtained."

Block or hard greases are of definite utility in many of the heavyindustries where they perform a special lubrication service. They areuseful for instance, in the lubrication of the journals of steel millrolls, paper mill rolls, railway driving journals and in the rod cupbearings of locomotives where bearing temperatures are high. They arealso widely. used in the lubrication of heavy equipment, particularly onthe large open bearings of such equipment where the use of soft greasesis considered unacceptable. In many instances the use of block grease ispreferred over oils or soft greases by reason of the fact that a blockgrease, suitable to the purpose, provides uniform lubrication over longperiods of time with less labor, attention and trouble.

Block greases vary widely in their compositions and in their methods ofcompounding and processing, depending mainly on the specific purposesfor which they are intended to be used. In general, however, they arecharacterized by being relatively hard, molded products usually in theform of blocks or sticks which retain their shape not only atatmospheric temperatures but at temperatures above actual operatingtemperatures encountered in use. In addition, the ideal block greasepresents an oily, or slick, and nonadhesive surface to the bearing onwhich it is used and should'wear away, due to rubbing or drag on thebearing, only as fast as it is necessary to provide uniform and adequatelubrication. The achievement of such a block grease for a specifiedlubrication service is somewhat of a rarity and is now accomplishedlargely through hit or miss experimentation rather than by logical,systemized, controlled testing and examination.

Certain empirical tests such as consistency or penetration tests, andmelting or dropping point tests have been applied to block greases andare useful for measuring apparent hardness and melting pointrespectively, but these tests taken singly or together are not adequateor sufficiently reliable in their results to render possible accuratelypredicting the rate of feed or block consumption of the grease underdifferent conditions of use. Further, the results of these tests are notreliable or conclusive guides in duplicating wear performance valueswith different greases made by other methods of compounding.

In use, block grease is generally placed in a holder on the bearing tobe lubricated and the block is held in contact with the moving surfaceby spring pressure, or by simply its own weight, 1. e. gravity feed. Insuch use, experience has shown that the serviceability and consumptionrate of the block is affected not only by the melting point andconsistency of the grease but also upon its jell roperties and upon thedrag or tendency of the grease to adhere to the bearing and be pulled ortorn away from the block.

In addition the structure of the grease is important both as regardsstability of the compound and its strength or resistance to deformationwhen shaped or molded. The grease must be stable in that no deleteriouschanges occur in its composition either in the body portion of the blockor at the surface where it contacts with the hot moving metal part ofthe bearing. In some cases greases that at first appear satisfactorywill develop leaching of oil, oxidation and other effects associatedwith elevated tempera tures and ageing. These effects are sometimesaccelerated by conditions surrounding the use of the grease. The greaseshould not be too hard or non-wearing lest insufficient lubrication andconsequent serious damage result; and yet it should not become too softor pasty in use or there will be too much lubrication, grease will bewasted, and the life of the block will be short. In this latter casethere is also danger from inadequate lubrication unless special care andattention is given to renewal of the block. If the grease is too soft itmay spatter and be thrown clear of the bearing to contaminate productsprocessed by the machine and require excess labor in keeping the machineclean.

It is an object of the present invention to provide a test apparatususeful for research and control of the wear performance values orcharacteristics of blocks of hard grease under conditions closelyparalleling conditions of use of the grease in actual service.

A further object of the present invention is to provide means fordetermining the rate of feed or block consumption of block grease atdifferent bearing temperatures which rate of feed will be fairlyindicative of the wearing characteristics or life of a block of thegrease when subjected to similar temperatures in actual use.

A further object of the invention is the provision of apparatus formeasuring the wear resistance of a block of block grease based upon itsdrag characteristics, its jell properties and its use melting point,which apparatus shall be extremely sensitive to small changes in thesecharacteristics and in which error arising from reworking of the greaseis substantially avoided.

A further object of the invention is the provision of apparatus usefulfor accurately estimating the flow, drag and jell stability values of ablock grease as such values afiect its wear characteristics whenlubricatin bearings at different feed pressures. p

A still further object of the invention is the provision of such a testapparatus which shall be simple in construction and operation,inexpensive to build, accurate and reliable in use and which will enableaccelerated testing of the consumption characteristics of a number ofblocks of hard grease simultaneously.

The above and other objects are accomplished by the apparatus of thepresent invention as will be apparent from the following description andaccompanying drawings in which there is illustrated more or lessdiagrammatically, a preferred embodiment of the invention.

In the drawings,

Fig. 1 is a top plan view of a preferred form of apparatus of thepresent invention.

Fig. 2 is a front view partly in elevation and partly in section.

Fig. 3 is an end view in elevation of the apparatus; and

Fig. 4 is a detail vertical sectional View of the rack for supportingthe blocks of grease in test position on the machine.

Referring to the drawings and more especially to Figs. 2 and 3, the baseof the apparatus consists of a heavy flat rectangularly shaped member 5of wood or metal or the like, at each end of which is mounted a pair ofspaced, upright, angleironsupports or standards 6 and 1, respectively.Trunnioned between the supports in bear-- ings 8 and 9 respectively is aclosed end, smooth, machine surfaced hollow cylinder or drum [0, adaptedto be rotated by means of an electric motor II. The motor is mounted onthe base plate as shown and provided with a pulley 12 which drives abelt13 in engagement with a second pulley i4 keyed to trunnion I5 of thecylinder.

To provide for heating the cylinder and for maintaining it at anydesired constant temperature a heating fluid such as oil, water or steamis circulated through the cylinder. For this purpose cylinder trunnionsl5 and 16 extend slightly into the cylinder as shown, and are hollow forreceiving fluid conductin tubes 11 and I8 respectively. The trunnionsare welded as at l9 and 20 respectively, to the end walls of thecylinder to provide sealed or leak proof joints at these points and theoutside vertical faces of the welds are machined smooth to serve as boththrust bearings and centering means for the cylinder. Tubes l1 and I8are welded to the trunnions where they enter and leave for providingsealed fluid proof connections atthese points. The outer end of eachtube terminates in packing boxes or glands 2| and 22, respectively, inaccurate alignment with the axis .of the cylinder. Opposite the terminalends of tubes I1 and [8 the packing boxes are threaded to receive pipes23 and 24, respectively, for conducting heating fluid from a suitablesource not shown to and away from the cylinder. Tube [1 is curvedoutwardly inside the cylinder as at 25 and terminates at a point closelyadjacent the cylinder wall to provide for efficient circulation of theheating fluid. Advantageously pipe 24 may serve to deliver heating fluidto the cylinder while pipe 23 serves to carry it away;

Positioned immediately above cylinder I0 is a grease block rackconsisting of a pair of side rails 26 connected'together at their endsby strap like members 21. Between the side rails but preferably securedthereto as by welding are a plurality of vertically disposed rectangularshaped, open ended metal boxes forming metal walled compartments forreceiving the blocks of grease to be tested. Thebottom edges of thecompartments are arranged to conform to the curved surface of thecylinder. The rack is adjustable vertically to position the lower edgesof the holders a desired distance above the surface of the cylinder.This is accomplished by positionin the side rails 26 of the rack in openended slots or guide ways 29 in the ends of standards 6 and 1 andpermitting them to rest upon vertically adjustable stops or guide plates30. Stops 30 are also provided with elongated slots through which bolts3i pass for clampin the plates in the desired vertical position on thestandards. Thus, it may be seen that the rack is adjustable verticallyand may beremoved from the apparatus by simply lifting.

The rack is provided with four block grease compartments'which are alikein size and shape and are substantially square or cubical in shape. Eachcompartment is adapted to receive a block of grease, as shown, of a sizeto form a sliding fit within the compartment. For positively feeding orforcing the grease into contact with the cylinder, iron or lead weights32 of definite value and of a size to fit loosely within thecompartments are placed in the compartments on top of the grease. Forconvenience in handling, the Weights are provided with circular openings33.

Considering the rotation of cylinder I0 in Fig. 3 to becounter-clockwise as indicated by the arrow, standards 6 and 1 at theends of the cylinder are provided with cylinder scraper blade supportsdisposed as shown at 34 and 35, respectively. Adjustably secured to thescraper sup-- ports as by means of threaded stud bolts 36 brazed to thesupports are scraper blade bed plates 31. The plates ma be adjustedtoward or away from the cylinder and locked in position by means of nuts38. The scraper blades shown at 39' consist of thin narrow strips ofbrass or bronze of spring like temper, rigidly clamped to the scraperblade supports by means of cover plates 40 and winged clamping screws H.The blades are slightly longer than cylinder in so that they extend ashort distance beyond the ends of the cylinder, and are adjustable intoscraping engagement with the cylinder by loosening clamping screws 4|and moving the blades forward or backward.

As shown, two scraper blades and scraper blade support assemblies areused, positioned advantageously a little less than apart. The purpose ofthe blades is to remove as much of the grease as possible from cylinderID in order to prevent any substantial re-working of the grease.

Positioned beneath cylinder Hi to catch the grease removed by thescrapers is a pan 42. The pan simply rests on the base 5 of theapparatus and is arranged for a loose sliding fit between the standards.

In use, steam or hot water at the desired temperature is circulatedthrough the cylinder and the cylinder rotated for a period of about 10minutes or until the surface temperature of the cylinder reachesequilibrium. One to four sample blocks of grease trimmed to size arecarefully weighed and then placed in the compartment in the grease rack.A Weight of suitable value is next placed on top of the grease in eachcompartment and the machine operated at a definite speed for a certainlength of time, say, 2 hours. The machine is then stopped, the blocks ofgrease removed and Weighed and their loss in weight determined. Thegrease consumption may be expressed in grams per hour as calculated bydividing the loss in weight of the block in grams by the number of hoursduring which the block is in contact with the rotating cylinder. Thesimultaneous testing of two or more blocks of grease under identicalconditions of temperature, time and cylinder surface speed, etc.,enables quick and accurate comparison of the block consumptioncharacteristics of different greases.

If desired, the machine may be operated at different temperatures withthe same grease and a curve plotted to show the different consumptionvalues of the grease at these different temperatures. The change inslope of the grease consumption curve may be sharp or gradual ascovering a small or large temperatur range. Such curves are particularlyuseful for determining or predicting the service performance of a blockof grease that is to lubricate machinery whose temperature variesmarkedly.

With a set of grease consumption data for a particular range oftemperatures one is able to tell at a glance just about how the greasewill perform under a prescribed set of conditions.

The test apparatus described is simple in construction and operation andinexpensive to build. It provides a ready guide or gage useful forresearch and control of the wear performance values of block greases andgives results as regards block consumption which are closely coordinatewith results obtained in actual practice,

What I claim is:

1. A block grease testing machine comprising a hollow cylindrical drum,means for rotating said drum, means for circulating a heating fluidthrough the drum for maintaining the temperature of the drumsubstantially uniform and constant, means for supporting a plurality ofblocks of block grease in juxtaposition adjacent the drum and in rubbingengagement with the cylindrical surface of the drum, and a scraper bladein scraping engagement with the drum adapted to substantially completelyremove grease from said surface, whereby reworking of the grease onsubsequent rotation of the drum is avoided.

2. A machine for testing the consumption characteristics of blocks ofblock grease, comprising a smooth cylindrical surface rotatable aboutits longitudinal axis, means for maintaining said surface at asubstantially uniform, constant temperature, holding means forsupporting a plurality of blocks of block grease over said surface suchthat said blocks are positioned for rubbing engagement with the surface,weights adapted for insertion in said holder on top of the grease formaintaining a constant feeding pressure on the grease with respect tosaid surface, and a plurality of thin flexible scraper blades for saidsurface adapted to maintain the surface of the cylinder approaching saidblocks during rotation of the cylinder substantially free of grease,whereby reworking of the grease is avoided.

3. The subject matter of claim 2 wherein said holding means for theblocks of grease is adjustable toward and away from the cylindricalsurface.

4. The subject matter of claim 2 wherein said flexible scraper bladesare adjustable toward and away from the cylindrical surface.

5. The subject matter of claim 2 wherein said grease block holding meansis removable from the machine by simply lifting.

6. The subject matter of claim 2 wherein the cylindrical surface ismaintained at a uniform, constant temperature bycontact with acirculating heating fluid.

HERSCHEL G. SMITH.

